1. Field of the Invention
The present invention relates generally to protective sheets for magnetic disc cartridges, and more particularly to an attachment apparatus and method for attaching disc protective sheets to the interior surfaces of each half body section of a disc cartridge body.
2. Background of the Related Art
Protective sheets are often attached on the interior opposed surfaces that face one another on the half sections of the disc cartridge body. A magnetic disc is typically sandwiched between the protective sheets and rotates within the cartridge body. The protective sheets are adapted to sweep foreign materials and contaminants such as dust or dirt that come into contact with the disc in order to protect the disc.
Each disc protective sheet is punched from a web of unwoven cloth and has an outer perimeter shape that is slightly larger than the outer perimeter shape of a magnetic disc and follows the contour of the substantially circular magnetic disc.
In assembly process steps of the disc cartridge, such disc protective sheets are respectively attached, by an attachment apparatus for disc protective sheet, on surfaces opposite to the magnetic disc on each of the upper and lower halves or sections of the cartridge body. This attachment apparatus includes a supply mechanism for supplying disc protective sheets onto the inner surfaces of upper and lower halves carried by conveyer, etc., and a fixing mechanism for fixing the disc protective sheets at the periphery of recording/reproduction opening portions of the inner surfaces of the upper and lower halves. The fixing mechanism includes a head portion for pressing the disc protective sheets onto the inner surfaces of the upper and lower halves, wherein plural pressing pieces for pressing disc protective sheets are formed in a saw-tooth pattern and arranged perpendicular to the pressing surface onto the pressing surfaces for pressing the disc protective sheets of this head portion. These pressing pieces are formed so as to have the ability to press the disc protective sheet onto the peripheral edge portion of the recording/reproduction opening portion. In addition, a heat portion for heating the head portion is provided at the fixing mechanism.
In such an attachment mechanism, when the disc protective sheets are delivered to the internal surfaces of the upper and lower halves by the supply mechanism, the disc protective sheets are fixedly fused at peripheries of the recording/reproduction opening portions of the internal surfaces of the upper and lower halves by the fixing mechanism. The fixing mechanism presses the head portion heated by the heating portion onto the disc protective sheet. Because the saw-tooth shaped pressing pieces are heated by the heating portion, the head portion bites the disc protective sheets into the periphery of the recording/reproduction opening portions of inner surfaces of the upper and lower halves so that they are fixed.
In such an attachment apparatus for disc protective sheets, since the disc protective sheets are fixedly fused at peripheries of the recording/reproduction opening portions of the upper and lower halves and are only attached thereat, the attachment state of other portions of the disc protective sheet becomes unstable, resulting in instances where dust attached on the magnetic disc cannot be completely swept. Particularly, in the case of a magnetic disc onto which information signals are recorded at high density, when dust attached to the magnetic disc cannot be swept, recording/reproduction errors occur. Moreover, since such attachment unit is adapted so that the fixing mechanism partially presses the peripheries of the recording/reproduction opening portion of the upper and lower halves, the upper and lower halves may be deformed. Further, since the disc protective sheets are adapted so that the entire surfaces are not fixedly fused at the upper and lower halves, there are instances where the disc protective sheet may be bent within the cartridge body. Also, the attachment position of the disc protective sheet deviates so that a portion of the disc protective sheet may be protruded toward the external from the recording/reproduction opening portion.
One object of the present invention is to provide an attachment apparatus for attaching a disc protective sheet to at least one half body section of a magnetic recording disc cartridge body. Another object of the present invention is to provide an attachment method for attaching such a disc protective sheet to at least one half of the cartridge body. A further object of the present invention is to provide both an apparatus and method for fixedly fusing a disc protective sheet onto a surface of a body section that faces a magnetic recording disc within the cartridge body when assembled. A still further object of the present invention is to provide such an apparatus and method for efficiently and reliably fixedly fusing the disc protective sheet onto the body section of the cartridge body.
An attachment apparatus according to this invention is for a disc protective sheet, for protecting a disc rotatably accommodated within a cartridge body formed by connecting a pair of upper and lower halves.
The apparatus of the invention includes a supporting mechanism with an outer perimeter shape that is slightly larger than the disc protective sheet. The supporting mechanism supports one half of a body section of a cartridge body to which the disc protective sheet is to be attached. A supply mechanism provides the disc protective sheet and delivers the sheet to the one half body section. The disc protective sheet has a cut out that is slightly larger than and corresponds to an opening formed in the one half body section. The disc protective sheet also has a thermal fusible layer provided on an attachment surface of the sheet. The opposite side of the sheet faces away from the one half body section. A fusing mechanism of the apparatus has an outer perimeter shape that is slightly larger than the disc protective sheet. The fusing mechanism is disposed opposite the supporting mechanism with the one half body section and the protective sheet sandwiched there between. The fusing mechanism fuses the thermal fusible layer of the disc protective sheet to the one half body section in order to secure the sheet to the body section.
The supporting mechanism is positioned beneath the fusing mechanism and the fusing mechanism and supporting mechanism are moved relative to one another. The disc protective sheet is delivered to the half body section of the cartridge body and faces the fusing mechanism when moved between the supporting mechanism and fusing mechanism. The fusing mechanism then fixedly fuses the disc protective sheet onto the surface of the half body section. The supporting mechanism comprises a supporting member for supporting the half body section. This supporting member is formed of an elastic member and is adapted so that groove portions are formed at the supporting surface side for supporting the half body section. The supporting member having the supporting surface at which groove portions are formed is easily deformed in a manner to absorb distortion such as warp of the half body section mounted on the supporting surface. This makes it possible to uniformly support the entire surface of the half. Thus, the disc protective sheet can be fixedly and securely fused onto the half.
Moreover, the engagement portion of the positioning mechanism for carrying out positioning of the cartridge body is engaged with the opening of the half. Further, in fixedly fusing the disc protective sheet onto the half, the half is pressed toward the supporting mechanism side by a pressing mechanism. The disc protective sheet is provisionally fixed or attached at the peripheral edge portion of the opening of the half body section by provisional attachment before it is fixedly fused onto the half, thereby making it possible to securely fuse the attachment surface of the disc protective sheet at a predetermined position.
In another embodiment of the invention, an attachment method is provided for attaching a disc protective sheet onto a surface of at least one half body section of a cartridge body for protecting a magnetic disc held within the cartridge body. When assembled, the cartridge body which is formed of upper and lower half body sections can include a disc protective sheet on each of the half body sections sandwiching the magnetic disc therebetween.
The method includes a step of supplying a disc protective sheet to a half body section. The disc protective sheet has a cutout that corresponds to an opening provided in the half body section. The opening is provided in the half body section for exposing a portion of the magnetic disc to the exterior of the cartridge body. The disc protective sheet also has a thermal fusible layer provided on an attachment surface of the sheet for attaching the sheet to the one half body section. When the cutout in the sheet is positioned corresponding to the opening in the half body section, a step of fusing the thermal fusible layer to the half body section is conducted to fixedly fuse the sheet to the body section.
In one embodiment, prior to the step of fixedly fusing the sheet to the half body section, the step of fusing the thermal fusible layer around the peripheral edge of the cutout to the half body section around the peripheral edge of the opening is performed. This step is conducted to provisionally fix or attach the disc protective sheet to the half body section.
Still further objects of this invention and more practical merits obtained by this invention will become apparent from the description of embodiments which will be given below.